The invention relates to an intravascular blood flow sensor (200) comprising a guidewire or catheter (202) for intravascular insertion, and a vibration sensor (206) arranged and configured to provide a vibration sensor signal indicative of an oscillation frequency of blood flow propagating along a main direction (L) of intravascular blood flow. The vibration sensor comprises a flagellum (206.1) that extends from the catheter or guidewire (204) in the main direction of intravascular blood flow and is elastically deformable in a direction perpendicular to the main direction of intravascular blood flow by the blood flow oscillations.
